Antennas with dipole radiating elements, both low frequency range and high frequency range, are commonly used in the communications industry.
Particularly, panel-type base station antennas, such as those used in mobile communication systems, are often dual polarization antennas. That is, these antennas often radiate radio frequency (RF) signals/energy on two opposite polarizations. Most dual polarization antennas are made with dual polarized elements, either by including a single patch element fed in such a manner to create a dual polarized structure, or by combining two linear polarized dipoles into one, thereby making a single, dual polarization element.
Conventional, dual polarization dipole radiating elements often have problems with beam width stability. It is, therefore, desirable to provide antennas with dipole radiating elements with improved beam width stability.
Additionally, many conventional panel-type base station antennas are multi-band (e.g., dual band or triple band) antennas. In such antennas, there are often problems with resonance from high band dipole radiating elements creating interference with low band frequencies. It is, therefore, desirable to provide antennas with reduced interference due to resonance from high band radiating elements.
It is further desirable to improve cross-polarization (ratio of power in a desired polarization to power in the opposite polarization) in dipole antennas.
Still further, antennas that include a plurality of dipole radiating elements may experience issues with poor isolation between adjacent radiating elements. It is, therefore, desirable to provide features that improve isolation between opposite polarities of adjacent radiating elements.